The present invention relates to the design, construction, and method of installation of equipment on equipment racks, and more particularly to the design, construction, and method of installation of equipment on aircraft equipment racks using hinge members to improve access to system connections.
The aircraft industry currently employs overhead racks attached to frames or frame structure to support equipment packages adjacent to the aircraft""s frames. These racks are typically installed by fastener attachment to the frames, or associated frame structure, prior to installation of the equipment packages. Wiring supporting the equipment packages is typically located in wire hangers supporting wiring banks and brought to general locations where the equipment packages will be located. The individual pieces of equipment are then mounted on the preinstalled racks and typically bolted in position. Following equipment installation on the rack assemblies, an installation mechanic will pull the wiring from the adjacent wiring banks to make connections into the equipment packages. A drawback of the existing rack system is that access for this type of installation is often difficult due to the structure of the rack assembly itself. Access for this type of installation is often made more difficult on existing aircraft, where in addition to the original wiring banks, structure of the rack assembly, and installed equipment, other equipment and structure may have been installed or retrofitted during the service life of the aircraft.
Existing rack assembly designs employ various structural members to support the equipment. Structural members may comprise vertical rails formed of angle shapes and U-shaped channels, flat plate forming equipment shelves, adjustable mounting fittings such as turnbuckle assemblies to locate the racks, and mechanical fasteners to join these members to themselves and the aircraft structure. Generally, aircraft safety requirements provide that additional support structure must be utilized to restrain motion of the rack assemblies. This additional support structure usually comprises diagonal support braces and additional stiffener members. A drawback is that installation of this additional structure, in addition to the vertical supports typically used to support the weight of the rack assembly and equipment package to the aircraft structure, provides a difficult access path for mechanics to reach the equipment to make the wiring and other equipment connections.
On wide body aircraft there is generally sufficient space in the overhead compartments for additional wiring and components for retrofit on the aircraft following initial construction. An example of this includes antenna system installation, which requires, in addition to the two antennas, power converters and power supplies for each. The power converters and power supplies have the additional restriction that their location must be within about two feet of each antenna. Such retrofit requires sufficient space for the equipment structure, the equipment, the necessary wiring, and any mechanical connections. Retrofitting this antenna equipment on existing aircraft, within the space limitation discussed above, must be performed within time constraints of aircraft down time, and with the drawback that surrounding structure and components could limit access into an existing design equipment rack.
There is a need for a less expensive and simpler method to provide the mechanic access to new installation or retrofitted equipment packages to make wiring and mechanical connections. A simpler structural design requiring fewer parts and a method of providing access for wiring interconnect to equipment before it is positioned and fastened to the rack assembly is desirable.
The present invention addresses these needs and past design drawbacks by providing a rack installation method and design that permits access to the associated equipment for interconnection activity prior to positioning the equipment in its final fixed position. The rack assembly and method of installation of the present invention relies on material forms such as flat sheet or plate metal, unshaped channel, angle shapes, and fasteners. At least one male hinge is incorporated in the rack structure which allows the equipment weight to be temporarily supported by the rack structure and provides an accessible equipment orientation for wiring. The male hinge(s) extends outwardly from the main body of the rack structure, permitting an equipment package to initially hang supported by the male hinge(s) along one of the package sides, vertically below the rack structure, and rotated about 90 degrees down from its final fixed position. This package position provides ease of access for a mechanic to reach the equipment electrical and mechanical connections. The mechanic can then perform cabling interconnect activities with unobstructed access to the equipment packages and greater access to the adjacent cable banks. When interconnect activities are complete and testing performed, the mechanic rotates the package about 90 degrees to its final fixed position.
The equipment package comprises the necessary equipment pre-mounted on a flat plate structure of suitable material for strength and weight, optional stiffener member(s), pre-bored equipment fastener holes which may be through bores or threaded bores, and at least one female hinge member. The at least one female hinge member comprises at least one opening in the flat plate to receive the at least one male hinge of the rack structure. A rod of about one quarter inch (0.64 mm) diameter spans the female hinge opening(s) and provides the axis of rotation for the equipment package about the male hinge(s).
In another aspect of the invention, a plurality of quick turn, eg. one-quarter turn, fasteners are provided to improve both installation and subsequent removal of the equipment package. These fasteners permit a single mechanic to swing the equipment package up to its installed position and, while holding the package in position, fasten the package to the rack structure. The rack structure is provided with mating fastener ports for the one-quarter turn fasteners. Similarly, for subsequent maintenance work, a single mechanic can support the weight of the equipment package while simultaneously releasing the quarter-turn fasteners.
The hinge(s) may also be reversed, wherein the male hinge(s) form a structural part of the equipment package, and the female hinge(s) form a structural part of the rack structure. Additionally, the hinge design may be varied in the form of a male pin which slides into the female hinge, or a door hinge design employing female type hinge members on both the rack structure and the flat plate of the equipment package may be used with a separate male pin joining the two female hinges. The female hinge(s) may also incorporate flat or rolled plate in place of the tack welded rod to simplify the hinge design.
In another aspect of the invention, an upper plate, forming a drip shield for the equipment package below, may form an integral part of the rack structure, or the drip shield may be incorporated as the flat plate of the equipment package.
The equipment package may also comprise a box-like enclosure surrounding the equipment mounted therein. In this aspect of the invention the equipment package, when swung up to its installed position, contacts an opposed plate section mounted to the rack structure, providing total enclosure of the equipment. Wiring clearance openings are employed for this aspect, with the potential for hermetically sealing the enclosure.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the invention.